Tumour-cell-derived complement components C1r and C1s promote growth of cutaneous squamous cell carcinoma

Summary Background Incidence of epidermal keratinocyte-derived cutaneous squamous cell carcinoma (cSCC) is increasing worldwide. Objectives To study the role of complement classical pathway components C1q, C1r and C1s in the progression of cSCC. Methods The mRNA levels of C1Q subunits, C1R and C1S in cSCC cell lines, normal human epidermal keratinocytes (NHEKs), cSCC tumors in vivo and normal skin were analyzed with quantitative RT-PCR. The production of C1r and C1s was determined with Western blotting. The expression of C1r and C1s in tissue samples in vivo was analyzed with immunohistochemistry and further investigated in human cSCC xenografts by knocking down C1r and C1s. Results Significantly elevated C1R and C1S mRNA levels and production of C1r and C1s were detected in cSCC cells, compared to normal human epidermal keratinocytes. The mRNA levels of C1R and C1S were markedly elevated in cSCC tumors in vivo compared to normal skin. Abundant expression of C1r and C1s by tumor cells was detected in invasive sporadic cSCCs and recessive dystrophic epidermolysis bullosa-associated cSCCs, whereas the expression of C1r and C1s was lower in cSCC in situ, actinic keratosis, and normal skin. Knockdown of C1r and C1s expression in cSCC cells inhibited activation of ERK1/2 and Akt, promoted apoptosis of cSCC cells and significantly suppressed growth and vascularization of human cSCC xenograft tumors in vivo. Conclusions These results provide evidence for the role of tumor cell-derived C1r and C1s in the progression of cSCC and identify them as biomarkers and putative therapeutic targets in cSCC. This article is protected by copyright. All rights reserved.Peer reviewe

Tumour-cell-derived complement components C1r and C1s promote growth of cutaneous squamous cell carcinoma

Background The incidence of epidermal keratinocyte-derived cutaneous squamous cell carcinoma (cSCC) is increasing worldwide. Objectives To study the role of the complement classical pathway components C1q, C1r and C1s in the progression of cSCC. Methods The mRNA levels of C1Q subunits and C1R and C1S in cSCC cell lines, normal human epidermal keratinocytes, cSCC tumours in vivo and normal skin were analysed with quantitative real-time polymerase chain reaction. The production of C1r and C1s was determined with Western blotting. The expression of C1r and C1s in tissue samples in vivo was analysed with immunohistochemistry and further investigated in human cSCC xenografts by knocking down C1r and C1s. Results Significantly elevated C1R and C1S mRNA levels and production of C1r and C1s were detected in cSCC cells, compared with normal human epidermal keratinocytes. The mRNA levels of C1R and C1S were markedly elevated in cSCC tumours in vivo compared with normal skin. Abundant expression of C1r and C1s by tumour cells was detected in invasive sporadic cSCCs and recessive dystrophic epidermolysis bullosa-associated cSCCs, whereas the expression of C1r and C1s was lower in cSCC in situ, actinic keratosis and normal skin. Knockdown of C1r and C1s expression in cSCC cells inhibited activation of extracellular signal-related kinase 1/2 and Akt, promoted apoptosis of cSCC cells and significantly suppressed growth and vascularization of human cSCC xenograft tumours in vivo. Conclusions These results provide evidence for the role of tumour-cell-derived C1r and C1s in the progression of cSCC and identify them as biomarkers and putative therapeutic targets in cSCC.</p

Tumor cell-specific AIM2 regulates growth and invasion of cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer. Inflammation is a typical feature in cSCC progression. Analysis of the expression of inflammasome components in cSCC cell lines and normal human epidermal keratinocytes revealed upregulation of the expression of AIM2 mRNA and protein in cSCC cells. Elevated levels of AIM2 mRNA were noted in cSCCs in vivo compared with normal skin. Strong and moderate tumor cell specific expression of AIM2 was detected with immunohistochemistry (IHC) in sporadic human cSCCs in vivo, whereas expression of AIM2 was moderate in cSCC in situ (cSCCIS) and low or absent in actinic keratosis (AK) and normal skin. IHC of cSCCs, cSCCIS and AKs from organ transplant recipients also revealed strong and moderate tumor cell specific expression of AIM2 in cSCCs. Knockdown of AIM2 resulted in reduction in viability of cSCC cells and onset of apoptosis. RNA-seq and pathway analysis after knockdown of AIM2 in cSCC cells revealed downregulation of the biofunction category Cell cycle and upregulation of the biofunction category Cell Death and Survival. Knockdown of AIM2 also resulted in reduction in invasion of cSCC cells and downregulation in production of invasion proteinases MMP1 and MMP13. Knockdown of AIM2 resulted in suppression of growth and vascularization of cSCC xenografts in vivo. These results provide evidence for the role of AIM2 in the progression of cSCC and identify AIM2 inflammasome function as a potential therapeutic target in these invasive and metastatic tumors.</p